Spin resonance properties of the two-dimensional electron gas

The electron spin resonance (ESR) of two-dimensional electrons (2DE) in Si/SiGe shows in addition to the absorption signal two types of indirect signals: a dispersion signal which reflects the frequency dependence of the electrical conductivity and a polarization signal which originates from the dependence of electric conductivity on the spin polarization of the 2DE. The occurrence of the polarization signal together with the dependencies of ESR on the direction of external magnetic field and on the electron concentration indicate that many body e−–e− correlation in the high mobility 2DE gas constitutes a specific phase very different from a 2D classical metal.